Print hammer mechanism



April 14, 1964 M. J. KITTLER y PRINT HAMMER MECHANISM Filed oct. 16, 1961 rw .j H R l z www 6. m mmm Cm/ y. V. 2J/ Zay/rf N Mxmwm. Hw Q WWQWM www mm N f/d f RMR/m WH 7 E ./O Yww WFY N/Y M B R0 .d /AB p r f V/ NMP y@ ..1 J 2 w. X F s a w Z 5 TW wp F ma. o m

United States nPatent 3,128,694 PRINT HAMMER MECHANISM Milton J. Kittler, Bloomfield Hills, Mich., assigner to Holley Carburetor Company, Warren, Mich., a corporation of Michigan Filed Oct. 16, 1961, Ser. No. 145,279 3 Claims. (Cl. 101--93) This invention relates generally to an electromechanical printer. More specifically, this invention relates to a print hammer mechanism that could be employed in a printer such as that disclosed in U.S. application Serial No. 138,- 157 entitled High Speed Printer and filed on September 14, 1961, in the names of Arvin D. McGregor and James M. Irvine, lr.

Accordingly, an object of the invention is to provide a hammer bank assembly that could be substituted for the hammer bank assembly shown in FIGURE 7 of the above referenced application Serial No. 138,157.

Another object of the invention is to provide a mechanical amplifier type print hammer mechanism in which there are but two moving parts, aided by spring means, in addition to the print hammer itself and a drive shaft.

A further object of this invention is to provide a hammer mechanism in which an eccentric shaft, in conjunction with a normally energized solenoid, cooperates with the above mentioned two moving parts to impart a high speed free ight to the print hammer as required to bring it into Contact with a print drum having characters to be printed formed thereon.

A still further object of the invention is to provide a high speed hammer mechanism which is simple in construction, economical to manufacture and automatic in operation.

These and other objects and advantages of the invention will become more apparent upon reference to the following specification and the attached drawings wherein:

FIGURE l is a fragmentary perspective view of a print hammer assembly embodying the invention;

FIGURE 2 is a diagrammatic view illustrating the nonprint paths of movement of selected points on the springiniiuenced impacting hammer embodied in the invention;

FIGURE 3 is a view similar to FIGURE 2, but showing the paths of these points during a print cycle.

Referring now to the drawings, a printer 10 embodying the invention is similar to the printer disclosed in the above referenced application in that it includes a suitable main frame 12 on which a hollow, cylindrical print drum or other means 14 having rows of characters 15 to be printed formed thereon is mounted for rotation in a manner to present the characters at a printing station 16. A print hammer mechanism 18 is arranged so as to provide a row of print hammers 20 adjacent the printer drum 14 at the printing station 16 so that selected hammers may impact associated characters on the drum, there being aS many print hammers as there are characters in a row. A record strip 22, such as a sheet of paper on which printing is to occur is moved through the print station 16 between the row of print hammers and the print drum, and a typewriter or other inked ribbon 24 may be positioned between the record strip and the print drum along the printing station.

In the particular printer disclosed herein, an elongated eccentric 25 is mounted on the printer frame 12 so as to be continuously driven, preferably at a speed having some timed relation with respect to lthe speed of rotation of the print drum 14. The underlying principle of the printer is that a relatively high energy mechanical drive is continuously operating so long as the printer power is turned on; however, the print hammers 2@ are maintained in a non-print position until the print hammer mechanisms are signaled and activated by low power electrical signals,

"lice in which event printing by any pre-selected print hammer takes place. After one complete cycle, each print hammer Ztl is returned and maintained in a non-print position until a print signal is again received.

With the above in mind, it can be seen that each print hammer 26 is retained in the non-print position shown by FIGURE l between appropriate guide members 26 and 28 by a suitable spring means 16. It will remain in this position until such time as it is impacted into contact with the print drum 14 by its actuating member 30. The actuating member 30 associated with each print hammer 2i) is constantly moving through what may be termed an orbital path by virtue of its being pivotally mounted on the eccentric 25 which is driven at a constant predetermined speed. The print hammer impacting end 32 of the actuating member 30 is biased by a spring 34 in such a manner that it continually rides up and down against the rear of the print hammer 20 throughout a complete revolution of the eccentric 25 so long as the other ramp end 36 of the actuating hammer 30 is free to pursue its normal resultant orbital motion. The resultant motions of the two ends 36 and 32 of member 30 under these (nonprint) conditions are as illustrated in FIGURE 2 by the paths of two points X and Y, respectively.

Hence, while the hammer mechanism is idling in the above manner, the print hammer 20 cannot be caused to come into contact with the print drum 14. This would he the situation so long as the trigger latch 38 of the trigger lever 40 is held out of the orbital path of the ramp end 36. A spring 42 is employed to normally hold each trigger lever 4t) against a stop 44, as shown by solid lines in FIGURE 1, and to thus place the trigger latch 38 in the path of the ramp end 36. However, the trigger lever 4t) is pulled downwardly to the broken line position of FIGURE l against the force of the spring 42 by means of an electromagnet 46 when it is desired that no printing take place.

Thus, the electromagnet 46 will normally be energized while the printer is in operation, and it will remain in this condition until such time as a signal is received from the computer with which the printer is used to print the particular character positioned opposite the print hammer involved. This signal would result in de-energization of the electromagnet 46, thus releasing its pull on the trigger lever 4l) and allowing the spring 42 to move the trigger lever 4i) against the stop 44. As mentioned above, the trigger latch 38 would now be positioned in the path of the ramp end 36 so as to obstruct the non-print orbital movement of point X shown by FIGURE 2. The ramp would thus come into contact with the latch 38 at the point X so that further lateral movement of point X would be prevented. However, the eccentric 25, which continues to rotate at its constant speed, also serves as a fulcrum and causes the thwarted lateral movement of the ramp end 36 to be transferred to the impacting end 32 of the actuating member 30. The resultant movement of the impacting end 32 is away from the rear of the print hammer 20 causing the spring 34 to be compressed.

Once the eccentric 25 has completed a portion of a turn, it will have raised point X on the ramp end 36 sufiiciently to remove it from its contact with the trigger latch 38. At this point, the latch 38 slides along the sloped surface and the lever 40 may move downwardly against the force of the spring 42. The new paths of the two points X and Y of the ends 36 and 32, respectively of the actuating member 30 during the portion of the cycle when the trigger latch 38 is preventing the normal free lateral movement of the ramp end 36 are as illustrated in FIGURE 3.

The disengagement of the contact between point X and the latch 38 is such that the compressed spring 34 biasing the impacting end 32 of the actuating member 30 3 will immediately snap the impacting end 32 toward its normal position against the rear of the print hammer 20 with sufficient force to cause the print hammer 20 to overcome its spring 48 and be propelled against the print drum 14, thereby causing a particular character, letter or number to be printed.

It will be understood that anchored ends of the springs 34, 42 and 48 are secured to anchor members 50, 52 and 54, respectively, the latter being mounted in any suitable manner on some portion of the printer frame 12. It will also be apparent that the guide members 26 and 28, the stop 44 and the base 56 on which the electromagncts 46 are mounted would also be secured in some manner to the printer frame. The drive shafts 58 and 60 of the eccentric and the print drum, respectively, would be driven in any suitable manner so as to have properly related rotational velocities.

It should also be apparent that there would be one print hammer 20, spring 48, impacting member 30, spring 34, latch lever 40, spring 42 and electromagnet 46 for each character in a row of characters formed on the drum. These elements could be separated in some manner by spacer plates so that they operate in adjacent slots formed by these plates; alternatively, spacers or other bearing means could be provided so that the above elements associated with a single print hammer would operate independently of the remaining mechanisms.

While but one embodiment of the invention has been disclosed, it can be appreciated that various modifications and a wide variety of cycle and phase timings may be possible without exceeding the scope of the appended claims.

What I claim as my invention is:

1. In a printer having a rotating print drum, the combination of a free fiight projectile type print hammer, first spring means for urging said print hammer away from said print drum, a rotating eccentric shaft, first means for at times impacting said print hammer, said first means being fitted freely around said rotating eccentric shaft and caused to move in an orbital path, second spring means connected to the impact end of said first means for urging said impact end against said print harnmer and thereby determining orbital path of the other end of said first means, second means for at times entering said orbital path of said other end of said first means, and thereby changing a portion of said orbital path, third spring means for urging said second means into said orbital path and third means for preventing said second means from entering said orbital path.

2. In a printer having a rotatable print drum, the combination of a free flight projectile type print hammer, a rotatable eccentric shaft, first spring means for urging said print hammer away from said print drum, first means for at times impacting said print hammer and imparting acceleration to said hammer, said first means being fitted freely around said eccentric shaft, second spring means cooperating with the impact end of said first means for urging said impact end against said print hammer and thereby causing the other end of said first means to move in an orbital path and for at times imparting acceleration to said first means, second means for at times entering said orbital path of one of said ends of said first means, third spring means for urging said second means into said orbital path, and third means for preventing said second means from entering said orbital path.

3. In a printer having a continuously rotated drum with rows of characters formed thereon, the combination of a row of print hammers positioned adjacent said print drum, each of said print hammers comprising a body mounted for reciprocating movement toward and away from said print drum, a continuously rotated eccentric shaft positioned on the side of said row of print hammers opposite said drum, a row of impact members fitted freely around said eccentric shaft for at times impacting one or more of said print hammers and projecting said impacted print hammers toward said print drum, the line of action of said print hammer passing through the center of said print drum, first spring means cooperating with said eccentric shaft for causing the ends of said impact member to move in an orbital path and for at times accelerating said impact member toward said print hammer, a trigger latch for at times entering a portion of the path of said orbital motion and for causing said impact member to compress said spring means until said impact member leaves said portion of said orbital path obstructed by said trigger latch, second spring means for urging said trigger latch into said orbital path, and an eleetromagnet for preventing said trigger latch from entering said orbital path while energized.

References Cited in the file of this patent UNITED STATES PATENTS 2,622,515 Wockenfuss Dec. 23, 1952 2,766,686 Fomenko et al. Oct. 16, 1956 2,787,210 Shepard Apr. 2, 1957 2,858,536 Johnston Oct. 28, 1958 2,873,666 Stiefel Feb. 17, 1959 2,895,411 Demer et al. July 21, 1959 2,897,752 Malmros Aug. 4, 1959 

1. IN A PRINTER HAVING A ROTATING PRINT DRUM, THE COMBINATION OF A FREE FLIGHT PROJECTILE TYPE PRINT HAMMER, FIRST SPRING MEANS FOR URGING SAID PRINT HAMMER AWAY FROM SAID PRINT DRUM, A ROTATING ECCENTRIC SHAFT, FIRST MEANS FOR AT TIMES IMPACTING SAID PRINT HAMMER, SAID FIRST MEANS BEING FITTED FREELY AROUND SAID ROTATING ECCENTRIC SHAFT AND CAUSED TO MOVE IN AN ORBITAL PATH, SECOND SPRING MEANS CONNECTED TO THE IMPACT END OF SAID FIRST MEANS FOR URGING SAID IMPACT END AGAINST SAID PRINT HAMMER AND THEREBY DETERMINING ORBITAL PATH OF THE OTHER END OF SAID FIRST MEANS, SECOND MEANS FOR AT TIMES ENTERING SAID ORBITAL PATH OF SAID OTHER END OF SAID FIRST MEANS, AND THEREBY CHANGING A PORTION OF SAID ORBITAL PATH, THIRD SPRING MEANS FOR URGING SAID SECOND MEANS INTO SAID ORBITAL PATH AND THIRD MEANS FOR PREVENTING SAID SECOND MEANS FROM ENTERING SAID ORBITAL PATH. 